Airjet spinning unit comprising a spindle-shaped component

ABSTRACT

An airjet spinning unit comprises a spindle-shaped component. The spindle-shaped component comprises a yarn withdrawal channel and is movable along said yarn withdrawal channel. The airjet spinning unit comprises at least one magnet for holding the spindle-shaped component in its operating position.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to an air jet spinning unit comprising a spindle-shaped component, which comprises a yarn withdrawal channel and is movable along the yarn withdrawal channel.

The present invention further relates to a spindle-shaped component for an airjet spinning unit having a yarn withdrawal channel, a cylindrical sliding surface for being received in the airjet spinning unit and a conically tapering spindle tip comprising the entry opening of the yarn withdrawal channel.

An airjet spinning unit of the above mentioned type is known from DE 10 2004 044 345 A1. A spring and a pneumatic cylinder are integrated into the known airjet spinning unit for the purpose of moving the spindle-shaped component. The complicated construction of the airjet spinning unit results in a high production outlay.

An airjet spinning unit is known from DE 195 01 545 A1, in which the elements for a motion and a support of the spindle-shaped component are not integrated into the airjet spinning unit. The spindle-shaped component is connected to a cylinder which is located outside of the airjet spinning unit and can as a result be moved along the yarn withdrawal channel. When the spindle-shaped component is being moved, the airjet spinning unit is completely open. The external pneumatic cylinder requires a large area of installation space in the airjet spinning device.

It is an object of the present invention to create an airjet spinning unit having a more simplified design.

This object has been achieved in that the airjet spinning unit comprises a magnet for holding the spindle-shaped component in its operational position. In the case of the spindle-shaped component, the object has been achieved in that the spindle-shaped component comprises a magnetic contact surface for fixing the spindle-shaped component in its operating position in the airjet spinning unit.

The only holding means for the spindle-shaped component in the airjet spinning unit is a magnet. It is of course self-evident that a number of magnets can be provided. Further fixing means or holding means in the airjet spinning unit or in the spinning arrangement are not necessary. Production and assembly of the airjet spinning unit are thus greatly simplified.

The spindle-shaped component is held in its operating position in the airjet spinning unit in such a way that a conically tapering spindle tip of the spindle-shaped component, which comprises the entry opening of the yarn withdrawal channel, is located in a vortex chamber, in which the fibre strand to be spun is imparted a spinning twist by means of a circulating air current. It is known that operational malfunction can occur in the airjet spinning unit, resulting in the vortex chamber having to be cleaned. In order to eliminate operational malfunctions, the spindle-shaped component is moved parallel to the yarn withdrawal channel in yarn withdrawal direction so that the spindle tip is moved out of the vortex chamber. By these means, fibre deposits can be removed from the vortex chamber.

The present invention has the advantage that no complicated designs and/or designs requiring very large installation space are necessary for the purposes of moving the spindle-shaped component. The spindle-shape component can be supported in a very simple cylindrical holding fixture in a base body of the airjet spinning unit and can be moved along the cylindrical holding fixture. In order to hold the spindle-shaped component in its operating position, at least one magnet can be arranged in the base body. The magnet interacts with the magnetic contact surface provided on the spindle-shaped component and holds the spindle-shaped component in its operating position. In accordance with a further advantageous embodiment, at least one magnet can be arranged on the spindle-shaped component or on a holding element connected to said spindle-shaped component. In this embodiment, the magnet interacts with a magnetic contact surface on the base body of the airjet spinning unit. For the purposes of eliminating operational malfunctions, the spindle-shaped component in both embodiments can be moved in the opposite direction to the magnetic force along the yarn withdrawal channel in yarn withdrawal direction so that the spindle tip is removed from the vortex chamber.

In the simplest case, the spindle-shaped component can be moved manually by service personnel. The use of a simple fixing means also permits easy removal of the spindle-shaped component from the airjet spinning unit and replacement by another spindle-shaped component.

It can also be advantageous for the movement of the spindle-shaped component along the air spinning machine to be effected by a travelling maintenance device, a so-called service robot.

In an embodiment of the present invention it can be advantageous that a lever, in particular a pivoted lever, is provided for moving the spindle-shaped component. The lever is advantageously fixed to the base body and connected to the spindle-shaped component by a detachable lock-in connection, so that the spindle-shaped component remains easy to replace.

The magnetic contact surface for holding the spindle-shaped component in its operating position is advantageously annular and can be arranged concentrically to the cylindrical sliding surface. In a further embodiment, the spindle-shaped component comprises a number of components, advantageously three components. A first component comprises the cylindrical sliding surface. The first component advantageously is made of a material which provides good sliding properties in relation to the material of the base body. A synthetic material or a brass or bronze material is advantageous for the first component. The cylindrical sliding surface can also comprise a coating. The second component of the spindle-shaped component comprises the conically tapering spindle tip with the entry opening of the yarn withdrawal channel. The conical outer contour of the second component is advantageously divided into areas having varying concinnity, wherein the cone angle decreases toward the spindle tip. A third component of the spindle-shaped component can comprise the magnetic contact surface for fixing the spindle-shaped component in its operating position. The third component is advantageously formed by a steel ring, which is fixed to the first component.

In a further advantageous embodiment of the present invention it is provided that the spindle-shaped component consists of two components. This embodiment is advantageous when the first component is made of a magnetic material, for example steel. The magnetic contact surface for holding the spindle-shaped component in its operating position can be integrated into the first component, so that the third component can be omitted. The spindle-shaped component consists therefore of one first component, which comprises the cylindrical sliding surface and the magnetic contact surface, and of a second component, which comprises the spindle tip.

In a further advantageous embodiment it can be provided that the spindle-shaped component comprises an injector channel which opens into the yarn withdrawal channel, and also comprising a compressed air supply for supplying the injector channel. The compressed air supply is suitable for mounting a compressed air tube. The injector channel can be supplied with compressed air for a piecing process in such a way that a defined airstream is generated in the yarn withdrawal channel. By means of the injector channel, an airstream, flowing towards the spindle tip, can be generated in the yarn withdrawal channel, which serves to guide back a yarn end through the airjet spinning unit in the opposite direction to the yarn withdrawal direction. It can also be provided that a circulating airstream can be generated in the yarn withdrawal channel by means of the injector channel. A circulating airstream in the yarn withdrawal channel is in particular then advantageous when a piecing process is carried out without the auxiliary yarn.

The present invention has the advantage in that the length of the yarn withdrawal channel in the spindle-shaped component is relatively small. The shortest possible yarn withdrawal channel in the spindle-shaped component can prevent a reduction in yarn quality, which could occur due to excessive contact of the spun yarn with the walls of the yarn withdrawal channel. The length of the yarn withdrawal channel in the spindle-shaped component measures advantageously less than 80 mm, and in particular less than 40 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

These and further objects, features and advantages of the present invention will become more readily apparent from the following detailed description thereof when taken in conjunction with the accompanying drawings wherein:

FIG. 1 shows an enlarged representation in longitudinal section of an airjet spinning unit according to the present invention,

FIG. 2 shows a top view in the direction of the arrow II of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

The airjet spinning unit as shown in FIG. 1 serves to produce a spun yarn 2 from a staple fibre strand 3. A drafting unit 4 is arranged upstream of the airjet spinning unit 1.

The staple fibre strand 3 to be spun is fed to the drafting unit 4 in drafting direction A and is withdrawn as a spun yarn 2 in yarn withdrawal direction B and fed to a winding device (not shown). The only partly shown drafting unit 4 is preferably a three-cylinder drafting device and comprises therefore three roller pairs, each of which comprises a driven bottom roller and an upper roller designed as a pressure roller. Only the delivery roller pair 5, 6 is shown, which borders the drafting zone of the drafting device 4. In a drafting unit 4 of this kind the staple fibre strand 3 is drafted to the desired degree of fineness in the known way. Directly downstream of the nipping line of the delivery roller pair 5, 6 of the drafting unit 4, a thin fibre strand 7 is present, which is drafted, but is still twist-free.

The fibre strand 7 is fed via a fibre feed channel 8 to the air jet spinning unit 1. Located downstream thereof is a so-called vortex chamber 9, in which the fibre strand 7 receives its spinning twist, so that the spun yarn 2 is formed, which is subsequently withdrawn through a yarn withdrawal channel 10.

A fluid device generates a vortex current during the spinning process in the vortex chamber 9 by means of blowing in compressed air through compressed air nozzles 11, which run tangentially into the vortex chamber 9. In the airjet spinning unit, the compressed air is fed during operation via a compressed air channel 12. From the compressed air channel 12, the compressed air reaches at first a ring channel 13, which surrounds the vortex chamber 9, to which ring channel 13 said compressed air nozzles 11 are directly connected. The compressed air exiting out of the compressed air nozzles 15 is discharged via an evacuation channel 14. The channel 14 is arranged annularly surrounding the spindle-shaped component 15, which comprises the thread withdrawal channel 10. The spindle-shaped component 15 is stationary during operation.

In the area of the vortex chamber 9, an edge of a fibre guiding surface 16, acting as a twist stop, is arranged, said fibre guiding surface 16 being slightly eccentrically arranged to the thread withdrawal channel 10 in the area of its entry opening 17. The entry opening 17 of the yarn withdrawal channel 10 is arranged at a conically tapering end of the spindle-shaped component 15. The conically tapering end is denoted as the spindle tip 18.

In the air jet spinning unit 1, the fibres to be spun are, on the one hand, held together in a fibre strand 7 and thus fed from the fibre feed channel 8 into the entry opening 17 of the thread withdrawal channel 10 essentially without a spinning twist. On the other hand the fibres in the area between the fibre feed channel 8 and the thread withdrawal channel 10 are exposed to the vortex current in the vortex chamber 9. The vortex current causes the fibres, or at least their end areas, to be driven away radially from the entry opening 17 and wound around the fibres already entering the yarn withdrawal channel 10. Therefore, the yarns 2 produced by the above described airjet spinning unit 1 exhibit a core comprising fibres or fibre areas extending essentially in thread longitudinal direction without any significant twist, and an outer area in which the fibres or fibre areas are wound around the core. An air jet spinning unit 1 of this type permits very high spinning speeds, which lie in the range between 300 and 600 m per minute.

If for any reason the fibre strand 7 or the yarn 2 breaks, the drafting unit 4 is first of all is stopped and the feed of staple fibre strands 3 is discontinued. The winding device (not shown) is also stopped. For the purposes of a restart of the spinning process, it may be necessary to remove fibre deposits caught in the vortex chamber 9. The spindle-shaped component 15 is moved for this purpose along the yarn withdrawal channel 10 in yarn withdrawal direction B so that the spindle tip 18 is removed from the vortex chamber 9. The fibre deposits clogging the vortex chamber 9 can be evacuated via an evacuation channel 14 connected to a vacuum source (not shown).

A base body 19 of the airjet unit 1 comprises a cylindrical holding fixture 20 into which the spindle-shaped component 15 with its cylindrical sliding surface 21 is assembled in a movable way. One or more magnets 22, in the embodiment shown, two magnets 22, are arranged in the base body 20. The spindle-shaped component 15 comprises a contact surface 23 made of a magnetic material which interacts with the magnet 22. The magnets 22 hold the spindle-shaped component 15 in its operating position. The magnetic contact surface 23 is annular in design. The contact surface 23 and the cylindrical sliding surface 21 are arranged concentrically around the yarn withdrawal channel 10.

The spindle-shaped component 15 can be moved in yarn withdrawal direction B along the cylindrical sliding surface 21 for the purpose of cleaning the vortex chamber 9. The movement of the spindle-shaped component 15 can be carried out manually by service personnel or by means of an automated maintenance carriage which is movable along the airjet spinning machine. A lever 24 for moving the spindle-shaped component 15 can be provided so that the spindle-shaped component 15 may be gripped easily. The lever 24 can be seen in FIG. 2. The lever 24 is designed as a pivoted lever and is fixed by means of a swivel axle 25 to the base body 19 of the airjet spinning unit 1. The lever 24 comprises projecting elements 26 which can be locked into place in a groove 27 of the spindle-shaped component 15. The lever 24 can be operated in its grip area 28 either manually or by automation, whereby the spindle-shaped component 15 is moved parallel to the yarn withdrawal channel 10. At the same time the lever 24 prevents the spindle-shaped component 15 from falling out of the cylindrical holding fixture 20 when the contact surface 23 is moved away from the effective area of the magnet 22. When it is necessary to remove the spindle-shaped component 15 completely from the airjet spinning unit 1, the spindle-shaped component 15 can be very easily lifted out of its lock-in connection in the lever 24 and removed from the airjet spinning unit 1. By swiveling the lever 24 back, the spindle-shaped component 15 is again moved in the opposite direction to the yarn withdrawal direction B and the spindle tip 18 reaches its operating position again in the vortex chamber 9. The magnets 22 fix the spindle-shaped component 15 at the contact surface 23.

An injector channel 29 which opens into the yarn withdrawal channel 10 is provided in the spindle-shaped component 15. Furthermore, a compressed air supply 30 is provided in the spindle-shaped component 15, which compressed air supply 30 can be supplied with compressed air at times for supplying the injector channel 29. The compressed air supply 30 is designed as a fitting 37 for a compressed air tube (not shown). The injector channel 29 serves to support a piecing process of the airjet spinning unit 1 and can open into the yarn withdrawal channel 10 in a way shown in FIG. 1, so that the compressed air flowing into the injector channel 29 generates an airstream in the yarn withdrawal channel 10 which flows in the opposite direction to the yarn withdrawal direction B. This permits one end of a spun yarn 2 to be guided back, in the opposite direction to the yarn withdrawal direction B, through the airjet spinning unit 1 to the drafting unit 4 and there to be integrated in the staple fibre strand 3. In an embodiment not shown, the injector channel 29 can open into the yarn withdrawal channel 10 in such a way that a circulating airstream is generated in the yarn withdrawal channel 10.

The spindle-shaped component 15 comprises three components 31, 32, 33. A first component 31 of the spindle-shaped component 15 comprises a cylindrical sliding surface 21, a part of the yarn withdrawal channel 10 and the compressed air supply 30. When a lever 24 is provided, the first component 31 then also comprises a groove 27. A second component 32 forms the conically tapering end of the spindle-shaped component 15 and comprises a spindle tip 18 and the entry opening 17 of the yarn withdrawal channel 10. The injector channel 29 extends from the compressed air supply 30 through the first component 31 and the second component 32 and opens within the second component 32 into the yarn withdrawal channel 10. The first component 31 of the spindle-shaped component 15 is made of a synthetic material. This provides the cylindrical sliding surface 21 with good sliding properties in relation to the holding fixture 20 in the base body 19. The sliding surface advantageously has a diameter of between 15 and 20 mm.

A third component 33 of the spindle-shaped component 15 is provided which comprises the magnetic contact surface 23. The third component 33 consists of a steel ring affixed to the first component 31. The steel ring 33 can for example be pressed onto the cylindrical sliding surface 21 and fixed there by means of threaded pins 35 (not shown). The distance between the contact surface 23 and the spindle tip 18 in the area of the entry opening 17 is of significance for the properties of the spun yarn 2. By means of altering the distance between the spindle tip 18 and the contact surface 23, the degree to which the spindle tip 18 projects into the vortex chamber 9 can be varied. Different dimensions can be achieved, for example, when only the height of the steel ring 33 is altered, while all other dimensions remain the same. Steel rings 33 having different height dimensions can hereby be used, or the position of the contact surface 23 can be adjusted by means of the application of washers between the first component 31 and the steel ring 33. This allows for tolerances in the spindle-shaped component 15 to be balanced out. In order to ensure the exact distance between the spindle tip 18 and the contact surface 23, it is possible to machine the contact surface 23 of an otherwise finished spindle-shaped component 15 in a final production step.

The second component 32 comprising the spindle tip 18 is inserted via cylindrical mounting surfaces 34 into the first component 31 and fixed by means of a threaded pin 35. In order to seal the transition of the injector channel 29 from the first component 31 into the second component 32, sealing rings 36 can be assigned to the mounting surfaces 34. In one embodiment of the present invention (not shown), the second component 32 can be pressed into the first component 31, which would omit the use of threaded pins 35 and sealing rings 36. The component 32 comprises a double cone on its outer contour, which has a small cone angle adjacent to the spindle tip 18 and adjoining, a large cone angle.

In the area of the exit opening of the yarn withdrawal channel 10, a wear-resistant adapter 39 can be applied to the spindle-shaped component 15. The adapter 39 can be made of a ceramic material and is inserted into the first component 31. In order to avoid negative influences on the yarn 2, the yarn withdrawal channel 10 is designed to be as short as possible in length. The length of the yarn withdrawal channel 10 measured from the entry opening 17 to the exit opening 38 is between 40 mm and 60 mm. 

1. An airjet spinning unit (1) with a spindle-shaped component (15) comprising a yarn withdrawal channel (10) and being movable along the yarn withdrawal channel (10), characterized in that the airjet spinning unit (1) comprises at least one magnet (22) for holding the spindle-shaped component (15) in its operating position.
 2. An airjet spinning unit according to claim 1, wherein a magnet (22) is arranged in a base body (19) of the airjet spinning unit (1).
 3. An airjet spinning unit according to claim 1, wherein a magnet (22) is arranged on the spindle-shaped component (15).
 4. An airjet spinning unit according to claim 1, wherein the airjet spinning unit (1) comprises a cylindrical holding fixture (20) for the spindle-shaped component (15), said spindle-shaped component (15) being movable along said holding fixture (20).
 5. An airjet spinning unit according to claim 1, wherein the spindle-shaped component (15) comprises a contact surface (23) made from a magnetic material which interacts with the magnet (22).
 6. An airjet spinning unit according to claim 1, wherein a lever (24) for moving the spindle-shaped component (15) is provided.
 7. A spindle-shaped component for an airjet spinning unit (1) comprising a yarn withdrawal channel (10), a cylindrical sliding surface (21) for mounting in the airjet spinning unit (1) and a conically tapering spindle tip (18) which comprises an entry opening (17) of the yarn withdrawal channel (10), wherein the spindle-shaped component (15) comprises a magnetic contact surface (23) for fixing the spindle-shaped component (15) in its operating position in the airjet spinning unit (1).
 8. A spindle-shaped component according to claim 7, wherein the magnetic contact surface (23) is annular in shape.
 9. A spindle-shaped component according to claim 7, wherein the magnetic contact surface (23) is arranged concentrically to the cylindrical sliding surface (21).
 10. A spindle-shaped component according to claim 7, wherein the spindle-shaped component (15) comprises an injector channel (29) which runs into the yarn withdrawal channel (10), and also comprises a compressed air supply (30) for supplying the injector channel (29).
 11. A spindle-shaped component according to claim 7, wherein the spindle-shaped component (15) consists of three components (31, 32, 33), wherein the first component (31) comprises the cylindrical sliding surface (21), wherein a second component (32) comprises the spindle tip (18), and wherein a third component (33) comprises the magnetic contact surface (23).
 12. A spindle-shaped component according to claim 11, wherein the first component (31) is made from a synthetic material.
 13. A spindle-shaped component according to claim 11, wherein the third component (33) is a steel ring (33) fixed to the first component (31). 